Images

Outlet channels were built at Castle Lake and Coldwater Lake (shown here) to stabilize water levels and prevent overtopping of the debris dams.

USGS geologists gathered samples by hand from vents on the dome and crater floor. Additionally, sulfur dioxide gas was measured from a specially equipped airplane before, during, and after eruptions to determine "emission rates" for the volcano.

USGS geologists gathered samples by hand from vents on the dome and crater floor. Additionally, sulfur dioxide gas was measured from a specially-equipped airplane before, during, and after eruptions to determine "emission rates" for the volcano. During eruptions, emission rates typically increased to 5 to 10 times their pre-eruptive value.

In this view the dome is 535 feet (163 meters) high and nearly 1/4 mile (0.4 kilometers) wide, making it taller than a 44-story building (or, nearly the height of the Washington Monument) and wider than the length of four football fields. Compare with image taken August 12, 1985 from the same location with the same camera.

Seismic station installation in Mount St. Helens's crater 1981 lava dome. USGS, in conjunction with the University of Washington, maintain seismic stations at Mount St. Helens. An increase in seismicity (earthquakes) is often the first precursor to an approaching eruption.

The U.S. Geological Survey, in conjunction with the University of Washington, maintain seismic stations at Mount St. Helens. An increase in seismicity (earthquakes) is often the first precursor to an approaching eruption.

Pinnacles left by erosion of fumaroles that formed as layered pyroclastic flow deposit released gas and solidified into chimneys that eventually eroded, Crater Lake, Oregon.

These pyroclastic-flow deposits of the climactic eruption of Mount Mazama, during which Crater Lake caldera formed, are eroded into spectacular spires at The Pinnacles on Wheeler Creek.

Lahars originating from Mount St. Helens after the 1980 eruption destroyed more than 200 homes and over 185 miles (300 kilometers) of roads. Pictured here is a damaged home along the South Fork Toutle River.

Between 1980 and 1986, Mount St. Helens' dome grew in different ways. From 1980 through 1982 the dome grew in periodic extrusions of stubby lava flows, called lobes. During this time frame Mount St. Helens' lobes grew at a rate of 3 to 10 feet per hour (1-3 meters/hour).

These measurements were used to study the erosion processes and to estimate the severity of the sedimentation problem. Rod person (lower left) and instrument persons (upper right) give scale.

Photo 15 of 15: Water level in sinkhole chimney stabilized since the previous day. View to south across the sinhole.

Photo 6 of 15: Sinkhole chimney at approximately 12 noon. View to south across the sinkhole.

Photo 7 of 15: Cars in a sinkhole. Auto mechanic’s garage starting to collapse into sinkhole. View to south across the sinkhole.

Photo 8 of 15: Community pool prior to collapse into the sinkhole. View to north across the sinkhole. (1:30 p.m)

Photo 9 of 15: Community pool collapsing into sinkhole at. Pool was roughly Olympic-sized and was about half full at the time of collapse. Impressive sounds of the rebar and concrete snapping, then the rush of water. View to north across the sinkhole. (1:30 p.m)

This collection is a group of 15 images (digitized slides) showing the sinkhole that opened late in the evening of May 8, 1981 near the intersection of South Denning Drive and West Fairbanks Avenue, Winter Park, Florida, USA.

Photo 2 of 15: Cars and house in a sinkhole. Auto mechanic’s garage intact. View to south across the sinkhole.

Photo 3 of 15: Community pool being undercut by a sinkhole. View to west across the sinkhole.

Photo 4 of 15: House within the sinkhole. View to north across the sinkhole.

Photo 5 of 15: House in a sinkhole. View to east across the sinkhole.